The present invention relates in general to telecommunications switching and more particularly to a method of determining network paths in a three stage switching matrix.
To provide path protection, or path switching, for network paths, there needs to be an ability to broadcast one path onto two paths from one network element and to select from one of the two paths at another network element. In considering a general broadcast/select scenario, wherein broadcast is from one path to many paths and select is from many paths to one path, a number of broadcast/select paths will be limited for one network element that uses a non-blocking three stage Clos matrix. Therefore, it is desirable to identify a path among any available paths in the matrix in order to perform the broadcast/select path protection.
From the foregoing, it may be appreciated by those skilled in the art that a need has arisen for a technique to identify a path through a switching matrix in order to perform broadcast/select path protection. In accordance with the present invention, a method of determining network paths in a three stage switching matrix is provided that substantially eliminates or reduces disadvantages and problems associated with convention path protection techniques.
According to an embodiment of the present invention, there is provided a method of determining network paths in a three stage switching matrix that includes identifying center stages available to each of three parts associated with either an originating stage or a terminating stage. Center stages available to any two of the three ports and available to all three ports are also identified. Center stages available to any one of the three ports but not the other two are determined as well as center stages not available to any of the three ports. A matrix connection is established through any center stage available to all three ports. If no center stage is available, then rearrangement candidates are determined to rearrange another matrix connection in order to free up a common center stage for all three ports.
The present invention provides various technical advantages over conventional path protection techniques. For example, one technical advantage is to identify paths through a switching matrix to perform a broadcast of one input onto two outputs. Similarly, another technical advantage is to identify paths through a switching matrix to select one output from two inputs. Another technical advantage is to limit the number of center stage rearrangements required in a switching matrix to accommodate a broadcast or selection requirement. Other technical advantages may be readily apparent to those skilled in the art from the following figures, description, and claims.